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Rationale LonP1 is an essential mitochondrial protease, which is crucial for maintaining mitochondrial proteostasis and mitigating cell stress. However, the importance of LonP1 during cardiac stress is largely unknown. Objective To determine the functions of LonP1 during ischemia/reperfusion (I/R) injury in vivo, and hypoxia-reoxygenation (H/R) stress in vitro. Methods and results LonP1 was induced 2-fold in wild-type mice during cardiac ischemic preconditioning (IPC), which protected the heart against ischemia-reperfusion (I/R) injury. In contrast, haploinsufficiency of LonP1 (LONP1+/−) abrogated IPC-mediated cardioprotection. Furthermore, LONP1+/− mice showed significantly increased infarct size after I/R injury, whereas mice with 3–4 fold cardiac-specific overexpression of LonP1 (LonTg) had substantially smaller infarct size and reduced apoptosis compared to wild-type controls. To investigate the mechanisms underlying cardioprotection, LonTg mice were subjected to ischemia (45 min) followed by short intervals of reperfusion (10, 30, 120 min). During early reperfusion, the left ventricles of LonTg mice showed substantially reduced oxidative protein damage, maintained mitochondrial redox homeostasis, and showed a marked downregulation of both Complex I protein level and activity in contrast to NTg mice. Conversely, when LonP1 was knocked down in isolated neonatal rat ventricular myocytes (NRVMs), an up-regulation of Complex I subunits and electron transport chain (ETC) activities was observed, which was associated with increased superoxide production and reduced respiratory efficiency. The knockdown of LonP1 in NRVMs caused a striking dysmorphology of the mitochondrial inner membrane, mitochondrial hyperpolarization and increased hypoxia-reoxygenation (H/R)-activated apoptosis. Whereas, LonP1 overexpression blocked H/R-induced cell death. Conclusions LonP1 is an endogenous mediator of cardioprotection. Our findings show that upregulation of LonP1 mitigates cardiac injury by preventing oxidative damage of proteins and lipids, preserving mitochondrial redox balance and reprogramming bioenergetics by reducing Complex I content and activity. Mechanisms that promote the upregulation of LonP1 could be beneficial in protecting the myocardium from cardiac stress and limiting I/R injury.

Human RNF213, which encodes the protein mysterin, is a known susceptibility gene for moyamoya disease (MMD), a cerebrovascular condition with occlusive lesions and compensatory angiogenesis. Mysterin mutations, together with exposure to environmental trigger factors, lead to an elevated stroke risk since childhood. Mysterin is induced during cell stress, to function as cytosolic AAA+ ATPase and ubiquitylation enzyme. Little knowledge exists, in which context mysterin is needed. Here, we found that genetic ablation of several mitochondrial matrix factors, such as the peptidase ClpP, the transcription factor Tfam, as well as the peptidase and AAA+ ATPase Lonp1, potently induces Rnf213 transcript expression in various organs, in parallel with other components of the innate immune system. Mostly in mouse fibroblasts and human endothelial cells, the Rnf213 levels showed prominent upregulation upon Poly(I:C)-triggered TLR3-mediated responses to dsRNA toxicity, as well as upon interferon gamma treatment. Only partial suppression of Rnf213 induction was achieved by C16 as an antagonist of PKR (dsRNA-dependent protein kinase). Since dysfunctional mitochondria were recently reported to release immune-stimulatory dsRNA into the cytosol, our results suggest that mysterin becomes relevant when mitochondrial dysfunction or infections have triggered RNA-dependent inflammation. Thus, MMD has similarities with vasculopathies that involve altered nucleotide processing, such as Aicardi-Goutières syndrome or systemic lupus erythematosus. Furthermore, in MMD, the low penetrance of RNF213 mutations might be modified by dysfunctions in mitochondria or the TLR3 pathway.

Research on healthy aging shows that lifespan reductions are often caused by mitochondrial dysfunction. Thus, it is very interesting that the deletion of mitochondrial matrix peptidase LonP1 was observed to abolish embryogenesis, while deletion of the mitochondrial matrix peptidase Caseinolytic Mitochondrial Matrix Peptidase Proteolytic Subunit (ClpP) prolonged survival. To unveil the targets of each enzyme, we documented the global proteome of LonP1+/- mouse embryonal fibroblasts (MEF), for comparison with ClpP-/- depletion. Proteomic profiles of LonP1+/- MEF generated by label-free mass spectrometry were further processed with the STRING (Search tool for the retrieval of interacting genes) webserver Heidelberg for protein interactions. ClpP was previously reported to degrade Eral1 as a chaperone involved in mitoribosome assembly, so ClpP deficiency triggers the accumulation of mitoribosomal subunits and inefficient translation. LonP1+/- MEF also showed Eral1 accumulation, but no systematic effect on mitoribosomal subunits. In contrast to ClpP-/- profiles, several components of the respiratory complex-I membrane arm, of the glutathione pathway and of lysosomes were accumulated, whereas the upregulation of numerous innate immune defense components was similar. Overall, LonP1, as opposed to ClpP, appears to have no effect on translational machinery, instead it shows enhanced respiratory dysfunction; this agrees with reports on the human CODAS syndrome (syndrome with cerebral, ocular, dental, auricular, and skeletal anomalies) caused by LonP1 mutations.

This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Science, ICT and Future Planning (NRF-2013R1A1A2010008, to BJP; 2009-0093815, to GYS; 2014R1A2A2A01005455, to KL; and NRF-2013R1A1A2063077, to SJL); the Progeria Research Foundation; the Ministerio de Economia y Competitividad of Spain; and the Red Tematica de investigacion cooperativa en cancer -Institute de Salud. The Institute Universitario de Oncologia is supported by Obra Social Cajastur-Asturias. CLO is an Investigator of the Botin Foundation., Lee, S.-J., Jung, Y.-S., Yoon, M.-H., Kang, S.-M., Oh, A.-Y., Lee, J.-H., Jun, S.-Y., Woo, T.-G., Chun, H.-Y., Kim, S.K., Chung, K.J., Lee, H.-Y., Lee, K., Jin, G., Na, M.-K., Ha, N.C., Bárcena, C., Freije, J.M.P., López-Otín, C., Song, G.Y., Park, B.-J

The gut microbiome is emerging as a key regulator of several metabolic, immune and neuroendocrine pathways1,2. Gut microbiome deregulation has been implicated in major conditions such as obesity, type 2 diabetes, cardiovascular disease, non-alcoholic fatty acid liver disease and cancer3,4,5,6, but its precise role in aging remains to be elucidated. Here, we find that two different mouse models of progeria are characterized by intestinal dysbiosis with alterations that include an increase in the abundance of Proteobacteria and Cyanobacteria, and a decrease in the abundance of Verrucomicrobia. Consistent with these findings, we found that human progeria patients also display intestinal dysbiosis and that long-lived humans (that is, centenarians) exhibit a substantial increase in Verrucomicrobia and a reduction in Proteobacteria. Fecal microbiota transplantation from wild-type mice enhanced healthspan and lifespan in both progeroid mouse models, and transplantation with the verrucomicrobia Akkermansia muciniphila was sufficient to exert beneficial effects. Moreover, metabolomic analysis of ileal content points to the restoration of secondary bile acids as a possible mechanism for the beneficial effects of reestablishing a healthy microbiome. Our results demonstrate that correction of the accelerated aging-associated intestinal dysbiosis is beneficial, suggesting the existence of a link between aging and the gut microbiota that provides a rationale for microbiome-based interventions against age-related diseases. Sin financiación 36.130 JCR (2019) Q1, 2/297 Biochemistry & Molecular Biology, 3/195 Cell Biology, 1/138 Medicine, Research & Experimental 15.812 SJR (2019) Q1, 2/271 Biochemistry, Genetics and Molecular Biology (miscellaneous), 5/2754 Medicine (miscellaneous) No data IDR 2019 UEM

Mitohormesis is a term used to define a biological response where the induction of a reduced amount of mitochondrial stress leads to an increment in health and viability within a cell, tissue, or organism. The mitochondrial stress response activated by a potentially damaging stimulus requires a coordinated dialogue with the cellular nucleus, known as mitonuclear communication. This interplay induced by the hormetic response in mitochondria relies in a variety of signals among which the most relevant ones are reactive oxygen species (ROS), mitochondrial metabolites, proteotoxic signals, the mitochondria-cytosol stress response, and the release of mitokines. The activation of the mitohormetic response increases lifespan in different animal models, from worms to mammals. Further, mitohormesis also enhances healthspan, particularly improving metabolism and immune system. Although multiple mediators and stress signals have been proposed to activate this protective mechanism, beneficial outcomes of mitohormesis are most probably due to an increase in mitochondrial ROS. Activation of other protective stress mechanisms as mitochondrial unfolded protein response or the increase in the expression of mitokines are also associated with the positive benefits exerted by mitohormesis. Herein, we review the different mitohormetic signals and pathways described from worms to mammals and their effects on health and survival. The identification and description of pathways and molecules implicated in the beneficial effects of mitohormesis will help understand the complex balance between death and survival in the face of mitochondrial damage and will allow to open a novel area of therapies aimed at improving health in humans.

Methionine restriction, i.e., a partial depletion of the essential sulfur amino acid methionine from nutrition, extends lifespan in model organisms including yeast, nematodes, mice and rats. Recent results indicate that this strategy also prolongs health span and longevity in 2 short-lived strains of mice (with the Lmna(G609G/G609G) or zmpste24(−/-) genotypes) that represent animal models of Hutchinson-Gilford progeria syndrome (HGPS). The beneficial effects of methionine restriction on HGPS could be linked to reduced inflammation, and improved DNA stability, as well as the normalization of lipid and bile acid metabolism. Previous work has established that behavioral, nutritional, pharmacological and genetic manipulations that extend longevity in model organisms are only efficient if they induce increased autophagic flux. Methionine restriction extends lifespan in Saccharomyces cerevisiae in an Atg5- and Atg7-dependent fashion, supporting the notion that methionine restriction may indeed mediate its antiaging effects through the induction of macroautophagy/autophagy as well. Based on these findings, we speculate that autophagy might constitute an actionable therapeutic target to treat progeroid syndromes.

Mitohormesis is a term used to define a biological response where the induction of a reduced amount of mitochondrial stress leads to an increment in health and viability within a cell, tissue, or organism. The mitochondrial stress response activated by a potentially damaging stimulus requires a coordinated dialogue with the cellular nucleus, known as mitonuclear communication. This interplay induced by the hormetic response in mitochondria relies in a variety of signals among which the most relevant ones are reactive oxygen species (ROS), mitochondrial metabolites, proteotoxic signals, the mitochondria-cytosol stress response, and the release of mitokines. The activation of the mitohormetic response increases lifespan in different animal models, from worms to mammals. Further, mitohormesis also enhances healthspan, particularly improving metabolism and immune system. Although multiple mediators and stress signals have been proposed to activate this protective mechanism, beneficial outcomes of mitohormesis are most probably due to an increase in mitochondrial ROS. Activation of other protective stress mechanisms as mitochondrial unfolded protein response or the increase in the expression of mitokines are also associated with the positive benefits exerted by mitohormesis. Herein, we review the different mitohormetic signals and pathways described from worms to mammals and their effects on health and survival. The identification and description of pathways and molecules implicated in the beneficial effects of mitohormesis will help understand the complex balance between death and survival in the face of mitochondrial damage and will allow to open a novel area of therapies aimed at improving health in humans.

Hutchinson–Gilford progeria syndrome (HGPS) is a disorder characterized by accelerated aging due to mutations in LMNA gene. The generation of mouse models of progeria has helped to unmask the molecular basis of this syndrome as well as to design therapeutic approaches aimed at improving the health span and life span of children affected. In this chapter, we describe two murine models developed for progeria research, named LmnaG609G/G609G and Zmpste24−/−, assessing the physical and molecular features that characterize them. We also recapitulate other mouse models available for the study of premature aging. Finally, we review the main therapeutic strategies that are being assayed to find a suitable treatment for HGPS.

Induced pluripotent stem cells derived from aged donors (A-iPSCs) usually show genomic instability that affects their utility and raises concerns about their safety. Now, a study highlights the importance of ZSCAN10-dependent recovery of glutathione-ROS homeostasis in counteracting the genomic defects in A-iPSCs.

Mitoproteases display an essential role in the preservation of mitochondrial homeostasis under regular and stress conditions. These enzymes perform tightly regulated proteolytic reactions by which they participate in mitochondrial protein trafficking, processing and activation of proteins, protein quality control, regulation of mitochondrial biogenesis, control of mitochondrial dynamics, mitophagy, and apoptosis. In this chapter, we have revised the physiological functions of the intrinsic mitochondrial proteases, analyzing their roles in the different compartments of this organelle and their connection to human pathology, primarily cancer, neurodegenerative disorders, and multisystemic diseases.

GK is supported by the Ligue contre le Cancer (équipe labelisée); Agence National de la Recherche (ANR); Association pour la recherche sur le cancer (ARC); Cancéropôle Ile-de-France; Institut National du Cancer (INCa); Fondation Bettencourt-Schueller; Fondation de France; Fondation pour la Recherche Médicale (FRM); the European Commission (ArtForce); the European Research Council (ERC); the SIRIC Cancer Research and Personalized Medicine (CARPEM); and the Paris Alliance of Cancer Research Institutes (PACRI). PB is supported by a SAF2012-36079 and CDS2010-00045 grants from MINECO, Spain. GM is funded by the Ramon y Cajal Program (RYC-2013-12751) and supported by Spain’s Ministerio de Economía y Competitividad, BFU2015-68539 and the BBVA foundation, BBM_BIO_3105. GM and GK are guarantors of the work presented herein, Fernández, Á.F., Bárcena, C., Martínez-García, G.G., Tamargo-Gómez, I., Suárez, M.F., Pietrocola, F., Castoldi, F., Esteban, L., Sierra-Filardi, E., Boya, P., López-Otín, C., Kroemer, G., Mariño, G.

International audience; Background Progeroid syndromes are genetic disorders that recapitulate some phenotypes of physiological ageing. Classical progerias, such as Hutchinson-Gilford progeria syndrome (HGPS), are generally caused by mutations in LMNA leading to accumulation of the toxic protein progerin and consequently, to nuclear envelope alterations. In this work, we describe a novel phenotypic feature of the progeria spectrum affecting three unrelated newborns and identify its genetic cause. Methods and results Patients reported herein present an extremely homogeneous phenotype that somewhat recapitulates those of patients with HGPS and mandibuloacral dysplasia. However, pathological signs appear earlier, are more aggressive and present distinctive features including episodes of severe upper airway obstruction. Exome and Sanger sequencing allowed the identification of heterozygous de novo c.163G>A, p.E55K and c.164A>G, p.E55G mutations in LMNA as the alterations responsible for this disorder. Functional analyses demonstrated that fibroblasts from these patients suffer important dysfunctions in nuclear lamina, which generate profound nuclear envelope abnormalities but without progerin accumulation. These nuclear alterations found in patients' dermal fibroblasts were also induced by ectopic expression of the corresponding site-specific LMNA mutants in control human fibroblasts. Conclusions Our results demonstrate the causal role of p.E55K and p.E55G lamin A mutations in a disorder which manifests novel phenotypic features of the progeria spectrum characterised by neonatal presentation and aggressive clinical evolution, despite being caused by lamin A/C missense mutations with effective prelamin A processing.

We have recently explored the in vivo functional and oncologic relevance of Lon protease (LONP1), an enzyme involved in mitochondrial quality control. We found that LONP1 is an essential protein for life and that it also performs a critical function in tumorigenesis by regulating the bioenergetics of cancer cells.

This work was supported by grants from Ministerio de Economía y Competitividad-Spain and Red Temática de Investigación del Cáncer (RTICC)., This work was supported by grants from Ministerio de Economía y Competitividad-Spain and Red Temática de Investigación del Cáncer (RTICC). C.L-O. is an Investigator of the Botín Foundation. V.Q. is a Ramón y Cajal Investigator with the Consolider-Ingenio RNAREG Consortium. The Instituto Universitario de Oncología is supported by Obra Social Cajastur and Instituto de Salud Carlos III (RTICC)., Bárcena, C., Quesada, V., De Sandre-Giovannoli, A., Puente, D.A., Fernández-Toral, J., Sigaudy, S., Baban, A., Lévy, N., Velasco, G., López-Otín, C.

We generated mice deficient in Lon protease (LONP1), a major enzyme of the mitochondrial quality control machinery. Homozygous deletion of Lonp1 causes early embryonic lethality, whereas its haploinsufficiency protects against colorectal and skin tumors. Furthermore, LONP1 knockdown inhibits cellular proliferation and tumor and metastasis formation, whereas its overexpression increases tumorigenesis. Clinical studies indicate that high levels of LONP1 are a poor prognosis marker in human colorectal cancer and melanoma. Additionally, functional analyses show that LONP1 plays a key role in metabolic reprogramming by remodeling OXPHOS complexes and protecting against senescence. Our findings demonstrate the relevance of LONP1 for cellular and organismal viability and identify this protease as a central regulator of mitochondrial activity in oncogenesis. This work was supported by grants from the Ministerio de Economı´a y Competitividad, Instituto de Salud Carlos III (RTICC), and Red Tema´ tica de Investigacio´ n Cooperativa en Enfermedades Cardiovasculares. The Instituto Universitario de Oncologı´a is supported by Obra Social Cajastur. K.W. is supported by the Strategic Young Researcher Overseas Visits Program for Accelerating Brain Circulation from Japan Society for the Promotion of Science. C.L-O. is an investigator for the Botin Foundation. Sí

Gene mutations that cause defects in the nuclear envelope are responsible for progeroid syndromes, characterized by exacerbated cell senescence and accelerated aging. Consequently, morphological abnormalities of the nucleus represent a cellular phenotype whose analysis allows for both the characterization of the consequences of particular mutations and the assessment of the impact of approaches aimed at reversing their pathological effects. To obtain reliable results, systematic and reproducible procedures are required. Here, we describe a simple fluorescence microscopy-based protocol to detect nuclear envelope alterations in the study of cellular senescence.

Gene mutations that cause defects in the nuclear envelope are responsible for progeroid syndromes, characterized by exacerbated cell senescence and accelerated aging. Consequently, morphological abnormalities of the nucleus represent a cellular phenotype whose analysis allows for both the characterization of the consequences of particular mutations and the assessment of the impact of approaches aimed at reversing their pathological effects. To obtain reliable results, systematic and reproducible procedures are required. Here, we describe a simple fluorescence microscopy-based protocol to detect nuclear envelope alterations in the study of cellular senescence.

Alterations in the architecture and dynamics of the nuclear lamina have a causal role in normal and accelerated aging through both cell-autonomous and systemic mechanisms. However, the precise nature of the molecular cues involved in this process remains incompletely defined. Here we report that the accumulation of prelamin A isoforms at the nuclear lamina triggers an ATM- and NEMO-dependent signaling pathway that leads to NF-κB activation and secretion of high levels of proinflammatory cytokines in two different mouse models of accelerated aging (Zmpste24−/− and LmnaG609G/G609G mice). Causal involvement of NF-κB in accelerated aging was demonstrated by the fact that both genetic and pharmacological inhibition of NF-κB signaling prevents age-associated features in these animal models, significantly extending their longevity. Our findings provide in vivo proof of principle for the feasibility of pharmacological modulation of the NF-κB pathway to slow down the progression of physiological and pathological aging.